This invention relates generally to a press for baling fibrous material, and more particularly to such a press having opposed boxes and a reciprocable pre-packing mechanism.
Fibrous material to be pressed and baled is usually fed in a loose or a bat form into a lint slide and/or a hooper from which it is fed through a side wall into a lint box located between a reciprocating tamper and the press box.
In such an arrangement the lint box is charged from the side at intervals and is further charged downwardly into the press box by means of the tamper which has a substantially constant-length stroke.
Existing presses are either of the single or multibox types, usually double boxes, wherein the boxes are arranged side-by-side for rotation about a center post. The tamper, normally comprising a piston operated tamper plate, is disposed over one of the boxes while the compression means, normally a hydraulic ram, is disposed over or under the other box so as to permit tamping of the fibrous material into one box and the pressing of the material into bales in the other box. When the fibrous material already tamped is to be fully compressed, the boxes are rotated through 180.degree. so as to dispose the filled box in line with the hydraulic ram, while the empty box from which a compacted bale has been removed, is now disposed beneath the tamper for filling and tamping of newly fed fibrous material. The boxes are again rotated through 180.degree. for disposing the tamped fibrous material in line with the hydraulic ram for compressing same as aforedescribed.
The difficulty with the side charging of fibrous material into the lint box is that the tamper must be in a fully retracted or upward position above the inlet opening for tamping a batch of material. And, because the tampers are charging the material with a substantially constant-length stroke, the material near the bottom of the lint box is obviously of lesser density than the tamped material near the upper portion of the lint box. Such an arrangement is therefore inefficient, since the tamper must be fully elevated for tamping each batch thereby increasing the time for the tamping cycle. Moreover, since uniform density throughout the height of the tamped batch is not readily controllable, the lint or upper box must normally be of a larger construction. The rotatable side-by-side box feature is likewise inefficient and cumbersome because of the space and the equipment required for such a press.
Moreover, the presently designed presses either use some type of door arrangement for exposing the compacted bale for removal, or a specially designed cylinder bears against an opposite side of the press box for causing the fibrous material to be compressed between the bottom ram and a top cylinder which closes the press box. The fibrous material is then extruded out of the press box to form a compact bale while the ram is moved upwardly and the top cylinder is retracted.